This invention relates to conservation of electrical energy for heating and cooling structural enclosures by use of a switch system that overrides conventional thermostatic controls to optimize on-and-off cycling and levels of current in relationship to temperature and power requirements of electrical heating and cooling mechanisms.
Use of power cycling to conserve energy consumed by electrical heating and cooling mechanisms is well known, but not with a conservation switch system that overrides conventional thermostatic controls to optimize on-and-off cycling and levels of current use in relationship to temperature and power requirements in a manner taught by this invention.
Conventional thermostatic control of on-and-off switching of electrical heating and cooling mechanisms requires mechanism structure for overheating above desired temperature settings for heating and overcooling below desired temperature settings for cooling. Between the overheating for heating and the overcooling for cooling, there are mechanism-off periods for mechanism rest while temperatures inside of heated and cooled structural enclosures fluctuate in oscillation cycles correspondingly. As a result, oscillational operation of the mechanisms controlled by conventional thermostats results in an undue use of power.
The present invention can eliminate the undue use of power, thus conserving electrical energy.
Although prior devices exist which might conserve energy, none accomplishes that task in a manner or as well as the present invention. An energy management control system for programmed cycle control to diminish this rate of use of power is described in U.S. Pat. No. 4,509,585, issued to Carney, et al. on Apr. 9, 1985. Carney, et al. is limited, however, to predetermined computer controls that are not application specific in a manner taught by this invention.
Examples of other known related but different energy management systems are described in the following patent documents. U.S. Pat. No. 5,816,491 issued to Berkeley, et al. on Oct. 6, 1998 discloses a method and device for conserving energy during peak loads by reducing fuel consumption. U.S. Pat. No. 5,678,758, issued to Takegawa, et al. on Oct. 21, 1997, describes a device for controlling a heating and cooling system by maintaining a temperature at a rate not detectable to occupants and saves energy at the same time through control of compressor run times. U.S. Pat. No. 5,428,252, issued to Walker, et al. on Jun. 27, 1995, described a computer system for adjusting power requirements of heating and cooling mechanisms to power available in power lines due to brownouts. U.S. Pat. No. 5,159,217, issued to Mortensen, et al. on Oct. 27, 1992, described a brownout protection and reset device which uses a microprocessor to delay resumption of operations for a preset time interval after a brownout. U.S. Pat. No. 5,115,968, issued to Grald on May 26, 1992, described a method and apparatus for controlling a heating and cooling system that uses a temperature error based on an on/off signal of a thermostat to control cycle time. U.S. Pat. No. 4,817,862, issued to Bhattacharya on Apr. 4. 1989, described a control valve for a gas heating system which includes thermostatic switching hardware. U.S. Pat. No. 4,817,705, issued to Levine, et al. on Apr. 4, 1989, described a thermostatic control device that uses a duty cycle basis in which ambient and desired temperatures are compared to arrive at an adjustment of run time so the thermostat does not have to be constantly adjusted to maintain a comfortable temperature. U.S. Pat. No. 4,655,279, issued to Harmon, Jr. on Apr. 7, 1987, described a system of controlling heating and cooling of a building with use of a thermostat with drift ramping and hold time to save energy.
The device of the present invention realizes much of its savings from the inherent over sizing built into most HVACandR systems. The equipment of such systems is typically sized according to the amount of conditioned area needed, desired temperature, load factors, interior and exterior architecture, exposures and regional climate. The regional temperature data used is of an extreme nature, the hottest or coldest climate conditions which can be experienced in the region annually for a thirty day period. With this in mind, it is a known factor that the equipment runs at peak load for a very brief period to handle such load demands.
The logic of the present invention takes advantage of the latter design criteria by cycling the temperature generating unit off and on in a programmed optimization schedule. The latter control attempts to satisfy the heating or cooling demand with less cumulative run time on the respective conditioning plant. The goal is to eliminate the superheating and cooling which widely occurs in commercial and residential environments.
The present device accomplishes its mission by constant polling the control line(s) for calls for running the temperature generating unit. This communication will state how long a call has been present, how long the equipment has run, and when it becomes satisfied or does not. With the information gathered internal decisions are made regarding run time adjustments. Demand levels may dictate adjustments to the program, increases dictating longer runs while decreases dictate shorter runs. The end result is to reduce consumption of electric, gas and oil driven equipment which the device is addressing.
Other advantages of utilizing the present device in addition to the energy saving benefits are realized in maintenance and safety areas. The unit prohibits short cycling of any compressor-driven cooling plant. The unit incorporates a delay feature which disallows any potentially damaging quick restart. The compressor will not start until four minutes have passed since the last call was completed.
The present device also addresses the inability of the equipment involved to reach a temperature satisfaction point. An automatic override in the present device allows the equipment to run without interruption, if after a preset time, for example forty minutes, the desired setting has not been reached. This feature eliminates the possibility of discomfort appearing due to a cycling schedule. The unit will attempt to save energy only while a window of opportunity exists. Saving energy with the sacrifice of personal, customer or goods temperature tolerances and comfort is not an option.
Also, the present device provides an internal diagnostic feature which will, in case of failure, remove the device from the circuit and return complete control to the original control means, such as a thermostat. Additionally the device has the ability to be taken out of line with a mechanical switch located on the device itself, this fail-safe is not voltage dependent and will complete the circuit under any circumstances.
Objects of patentable novelty and utility taught by this invention are to provide an energy-conservation moderating system which:
displaces conventional thermostatic single-cycle on-and-off switching of heating and cooling mechanisms with plural-cycle short-time on-and-off switching between temperature-band on-call extremes and temperature-band means of temperature-band fluctuation selectively;
operates the heating and cooling mechanisms in response to application-specific temperature detection;
conveys desired temperature differences from predetermined proximateness of the heating and cooling mechanisms to temperature-use positions selectively when not operating; and
restores the conventional thermostatic single-cycle on-and-off switching of the heating and cooling mechanisms automatically for failsafe backup operation when on-time duration of the short-time on-and-off switching exceeds a preset time.
This invention accomplishes these and other objectives with an energy-conservation moderating system which interfaces with the motor control mechanism of compressors for air conditioners, coolers, and freezers. The device also interfaces with the heating control mechanisms of boilers and furnaces. These two types of equipment will collectively be described by the terms cooling and heating systems or temperature difference generators.
The present device is designed to provide savings for the operation of a cooling or heating systems. The savings are obtained by reducing the total run time of a system""s compressor or heating plant. The savings are achieved without sacrificing occupant comfort for air conditioning or heating. The savings are also achieved while keeping the control area within the temperature requirements for food storage set by the United States Department of Agriculture (xe2x80x9cUSDAxe2x80x9d). The savings are achieved without increasing the wear on the equipment. The results of which is a reduction in the total cost to operate the cooling or heating equipment.
The present device operates in conjunction with the thermostat of a cooling/heating system. It does not replace the system thermostat nor can the device operate without the thermostat. The device intercepts the control signal from the thermostat and modifies the signal using a savings algorithm. This modified signal, the output signal, is then used as a replacement which is sent to the motor or heating control mechanism. It is through this modification of the control signal from the thermostat that the savings operation is performed.
The present invention incorporates a microcontroller that provides all logic operations to produce the savings. The microcontroller is constantly monitoring the control signal from the thermostat. When there is a signal from the thermostat to turn ON the compressor or furnace, this invention determines how to operate the motor or furnace control in order to reduce the total run time of the compressor or furnace. The invention then generates a replacement signal which is sent to the motor or furnace control. This effect of this replacement signal then allows the heating/cooling system""s compressor or furnace to operate at a reduced total run time. The control signal from the thermostat consists of two compressor or furnace control states: ON or OFF. This invention only modifies the ON signal from the thermostat to produce savings. The OFF signal is not modified. So when the control signal is OFF, the invention will always send an OFF signal to the compressor or furnace. When the control signal sends the device of the present invention an ON signal, then the device can send either an ON or OFF signal to the motor or furnace control. Therefore, the device will always be able to shut down the compressor or furnace during a thermostat call, but will not turn ON the compressor or furnace when there is no call.
The present invention has failsafe circuitry that xe2x80x9ckicks inxe2x80x9d when the main operation fails. This feature bypasses the savings operation and allows the control signal to pass through the device unaltered. During failsafe operation, the control signal from the thermostat is not intercepted by the device, but rather passes through a relay and continues to the motor or furnace control. When the failsafe circuitry kicks in, there will be no further control from the device and therefore no savings will be obtained while in failsafe mode.
The present invention incorporates a DPDT switch which can be broken down to operate as two distinct switches in a single package. These two switches are designated DPDT-1 and DPDT-2. The invention uses DPDT-2 as a power switch which allows the invention to be turned off for any purpose. When the device of the present invention is in the OFF position, the signal from the thermostat bypasses the internal operation of the invention completely. The thermostat""s input signal is physically connected to the inventions""s output via DPDT-1. When the invention is switched OFF, there is no contact by the control signal with the internal components of the invention. Therefore, in the OFF position, the replacement signal is identical to the control signal.
The present invention produces savings by reducing the total run time of a cooling system""s compressor or heating system""s furnace. These savings are achieved by modifying the control signal from the thermostat. It includes failsafe circuitry which is designed to operate in the case of a unit failure. Therefore, the invention allows the cooling or heating equipment to provide the same operational effects of a conventional heating/cooling system which uses just a thermostat alone but at a reduced operating cost.